The present invention relates to a zinc electroplating bath brightener and to improvements in the electrodeposition of zinc from aqueous, acid plating baths.
Heretofore, certain characteristics of conventionally utilized acid zinc bath formulations have rendered them in many instances somewhat impractical to use. For example, the bath formulations disclosed in U.S. Pat. No. 3,694,330, has a limiting factor in that only a rather low current density can be applied to a given article to produce a lustrous zinc deposit. Should the current density be raised to increase the speed of plating, very dark, course deposits of zinc would be plated on the article. Another common problem is that which occurs in using the bath formulations of U.S. Pat. No. 3,723,263 in that at bath temperatures of above 95.degree. F, the formulations encounter a severe loss of brightening ability.
Since electroplaters often prefer to plate at quite high current densities to facilitate high plating rates, a broad plating range and high bath temperature tolerance are very important.